Innovations in building construction techniques have resulted in what have generally become known as monolithic dome structures, such as disclosed in U.S. Pat. Nos. 4,155,967 and 5,918,438 that are incorporated herein by reference. Such monolithic dome structures exhibit high strength and heat efficiency and are generally formed by securing the peripheral marginal edge of an inflatable form to a footing, inflating the form so as to create a dome shape, applying one or more layers of foam to the inner surface of the form, preferably securing hanger members to the foam layer to which a metallic reinforcing mesh is attached, and applying one or more layers of a cementitious material to the inner exposed surface of the foam so as to embed the mesh and form a built-up high strength dome structure after curing of the applied layers. A sprayable cementitious material suitable for progressive layer buildup is commercially available as “Gunite” and “Shotcrete” that are mixtures of graded sand and cement. The inflatable form may be removed if desired and a coating applied to the outer surface of the thus formed dome structure to protect it from possible moisture and ultraviolet degradation.
The aforedescribed dome construction techniques lend themselves to alternative dome shapes and sizes. This is particularly significant when utilizing monolithic dome structures for airplane hangars that inherently are of substantial size. The innate strength of monolithic dome hangars provides protection for the aircraft from high winds, tornados, hurricanes, earthquakes, fire, burglary, sabotage and other natural and manmade hazards. Such structures also exhibit highly efficient heat energy and cooling characteristics, thus contributing significantly to environment conservation.
In forming monolithic dome building structures, at least one access opening to the interior of the dome structure is generally formed at ground level so as to accommodate a doorway structure that usually includes one or a pair of vertically hinged access doors. While suitable for conventional size access openings in dome structures, vertically hinged access doors, or alternatively roll-up type doors, are generally limited in size and thereby limit the size of the corresponding access opening formed in the wall of the dome structure.
Airplane hangars have traditionally employed aircraft entry doors that are necessarily relatively large, but are made light enough to enable relatively easy opening and closing. Examples of airplane hangar doors include single-fold lifting doors, bi-fold lifting doors, and sliding doors that stack to a side of the aircraft entry opening. Such hangar doors are susceptible to damage from high winds so as inhibit proper operation of the doors in addition to exposing aircraft within the hangar to possible wind damage. There thus exists a need for a high strength door for monolithic dome style hangars that can withstand the rigors of high winds and the like without compromising ease of opening and closing relative to an aircraft access opening.